TWI753664B - wind power plant - Google Patents

Abstract

The present invention provides a wind power generation device capable of improving both the securing of the power generation amount and the reduction of the load acting on the wind power generation device. The wind power generation device of the present invention has a normal operation mode and a low-load operation mode, and when the wind condition data exceeds the threshold for transitioning from the normal operation mode to the low-load operation mode, it operates in the low-load operation mode; once the wind condition data exceeds the normal The transition threshold value is changed from the normal operation mode to the low-load operation mode, and the transition threshold value is lowered for a certain period of time.

Description

wind power plant

The present invention relates to a wind power generator, and more particularly, to a wind power generator having the function of switching operation modes according to wind conditions to reduce the load acting on the wind power generator.

In terms of environmental protection, as a power generation device that does not use fossil fuels and suppresses carbon dioxide emissions, power generation devices that utilize renewable energy sources that can be obtained from nature, such as wind power and sunlight, are attracting attention. In particular, the wind power generation device can generate electricity more stably day and night by choosing a place where the wind speed and direction of the wind are stable, and it can also be installed in a place where the wind speed is higher and the wind condition is higher than on land. The sea with few changes is eye-catching.

The wind power generator is running while monitoring the wind conditions such as the wind speed and direction, the difference between the wind direction and the nacelle, that is, the yaw error. Stop the operation of the wind turbine. However, frequent stopping of the operation leads to a decrease in the amount of power generation and the like, which is not preferable. Therefore, unless the wind speed increases above the rated value, or the yaw error becomes very large, the load (hereinafter, simply referred to as "load") acting on the wind turbine becomes particularly large, and the wind turbine is expected to continue to operate. run. Therefore, there is proposed a method of reducing the load by changing from the normal operation mode to the low-load operation mode under similar wind conditions where the load increases.

The transition to a low load operating mode typically occurs when a value in wind condition data such as wind speed or yaw error exceeds a threshold. In the low-load operation mode, the load is reduced by limiting the rotational speed and power generation, and the power generation during this period is lower than that in the normal operation mode. In order to prevent the reduction of the power generation amount, the threshold value for transition to the low-load operation mode must be set as high as possible. However, when the normal operation mode is shifted to the low-load operation mode, a certain amount of time is required in order to avoid abrupt changes in the rotational speed and the generated power. If the transition threshold value is set high, the transition to the low-load operation mode may become slow and the load may increase. Therefore, in order to surely avoid an increase in load, it is necessary to lower the transition threshold. In order to secure the power generation amount and reduce the load at the same time, the setting of the transition threshold is a problem.

The threshold value for such transition to the low-load operation mode is disclosed in Patent Document 1, for example. In Patent Document 1, it is disclosed that when the wind speed or the turbulence degree index of the wind speed reaches a threshold value or more, the load suppression operation mode is selected, and the threshold value of the wind speed or the turbulence degree index of the wind speed can be changed according to the wind direction; When the turbulence index exceeds the threshold value, select the load suppression operation mode, and the threshold value of the turbulence index of the wind speed can be changed according to the wind direction and wind speed. [Prior Art Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open No. 2017-133441

[Problems to be Solved by Invention]

The wind power generator disclosed in Patent Document 1 adapts the transition threshold value of the turbulence index of the wind speed or the wind speed by considering the wind direction or the wind direction and the wind speed. However, according to the research of the present inventors, there is still room for further improvement in terms of both securing the power generation amount and reducing the load. That is, in Patent Document 1, for example, if the wind direction does not change, the transition threshold value of the wind speed or the turbulence degree index of the wind speed is the same. However, in many cases, it is considered that the wind condition lasts for a certain period of time, and once the transition from the normal operation mode to the low-load operation mode occurs, the transition from the normal operation mode to the low-load operation mode occurs continuously thereafter. Previously, no consideration has been given to the period during which this low-load operation mode is prone to occur.

According to the study of the present inventors, if the transition threshold value is set in consideration of the period during which the low-load operation mode is likely to occur, it is possible to further improve the balance between securing the power generation amount and reducing the load. An object of the present invention is to provide a wind power generator which can be improved in both securing the power generation amount and reducing the load acting on the wind power generator. [Technical means to solve problems]

In order to solve the above-mentioned problems, the wind power generation device of the present invention changes from the normal operation mode to the low load operation mode once the wind condition data exceeds the threshold value of the transition to the low load operation mode, and makes the transition from the normal operation mode to the low load operation mode. The threshold value is lowered for a specific period, and specifically, the wind power generator of the present invention is configured as described in the scope of the application.

Furthermore, the description in the scope of the patent application adopts a single citation for simplifying the citation relationship, but the present invention also includes the situation of adopting multiple citations, and further includes the situation of citing the claims of multiple citations multiple times. [Effect of invention]

According to the present invention, it is possible to improve both the securing of the power generation amount and the reduction of the load acting on the wind power generator. That is, according to the present invention, the transition from the normal operation mode to the low load operation mode can be accelerated under wind conditions where the possibility of operation in the low load operation mode is high, and the load acting on the wind turbine generator can be reduced. In addition, the threshold for transitioning from the normal operation mode to the low-load operation mode is restored to the normal transition threshold under wind conditions where the possibility of operation in the low-load operation mode is not high, so that reduction in the power generation amount can be prevented. Problems other than the above, configurations, and effects will be clarified by the description of the following embodiments.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In addition, in each drawing, the same code|symbol is attached|subjected to the same structure, and the detailed description is abbreviate|omitted in the overlapping part. [Example 1]

1 to 5, the wind power generator in the first embodiment will be described. FIG. 1 is an overall schematic configuration diagram of a wind power generator according to Embodiment 1 of an embodiment of the present invention. The wind power generator 1 shown in FIG. 1 has a rotor in a leeward type on the leeward side, and is provided with a rotatable rotor 4. The rotor 4 includes: a hub 2 having a rotating shaft (omitted from the figure); and a plurality of blades 3. It is installed on the hub 2. The rotor 4 is rotatably supported by the nacelle 5 via a rotation shaft not shown, and transmits the rotational force of the rotor 4 to the generator 6 in the nacelle 5 . The wind turbine generator 1 generates electric power by rotating the rotor 4 by receiving wind by the blades 3 , and rotating the generator 6 by the rotational force of the rotor 4 . On the nacelle 5, there is a wind direction anemometer 7 for measuring the wind direction and wind speed, and in the generator 6, there is a rotational speed sensor 8 for detecting the rotational speed, and a power sensor for measuring the effective power output by the generator (Fig. omitted in) etc. Further, the wind turbine generator 1 includes a pitch angle adjusting device 9 for each blade 3, and the pitch angle adjusting device 9 adjusts the angle (pitch angle) of the blade 3 with respect to the wind. The wind power generator 1 is configured to change the rotational energy of the rotor 4 generated by the wind by adjusting the wind force (air volume) received by the blades 3 by changing the pitch angle of the blades 3 by the pitch angle adjusting device 9 . Thereby, the rotational speed and the power generation can be controlled within a wide wind speed range. The wind turbine generator 1 includes a tower 10 that supports the nacelle 5 in a rotatable manner. The orientation of the nacelle 5 is called a yaw angle, and the wind turbine generator 1 includes a yaw angle adjusting device 11 that controls the orientation of the nacelle 5 , that is, the orientation of the rotating surface of the rotor 4 . As shown in FIG. 1 , the yaw angle adjusting device 11 is disposed between the bottom surface of the nacelle 5 and the upper end of the tower 10 , and includes, for example, at least an actuator (not shown) and a motor for driving the actuator. Based on the yaw angle target value output from the operation control device 12 via the signal line, the motor constituting the yaw angle adjustment device 11 rotates, and the actuator is displaced by a desired amount, whereby the nacelle 5 rotates to a desired yaw angle . The tower 10 is configured to support the load of the blade 3 via the hub 2, the nacelle 5, and the yaw angle adjustment device 11, and is installed on the ground. Further, the operation control device 12 constituting the wind turbine generator 1 controls the wind turbine generator by adjusting the torque of the generator 6 and the pitch angle adjustment device 9 based on the rotational speed (rotor speed) and the power output from the generator 6, etc. The generating power of 1 and the rotational speed of rotor 4. In addition, the operation control device 12 controls the yaw error, which is the angle of the rotor 4 with respect to the wind direction, by adjusting the yaw angle adjustment device 11, so that power generation can be continued even if the wind direction changes. In FIG. 1 , the operation control device 12 is shown as being installed outside the nacelle 5 and the tower 10 , but the operation control device 12 may be arranged inside the nacelle 5 or the tower 10 , and can also be installed in the wind power. Outside the power generating device 1 .

FIG. 2 shows an outline of the power generation operation of the wind turbine generator 1 . 2 shows the relationship between the generated power, the rotational speed of the generator, the torque of the generator, and the pitch angle with respect to the wind speed, and an outline of the power generation operation of the wind power generator 1 will be described using this figure. The horizontal axis of each graph represents the wind speed, and the further to the right, the faster the wind speed. In addition, the vertical axis of each graph shows that each value of the generated power, the rotational speed, and the generator torque increases as it goes up. Regarding the pitch angle, the upper part is the feathering (wind-out) side, and the lower part is the reverse (wind-receiving) side. The power generation is carried out within the range of the cut-in wind speed Vin when the rotor 4 starts to rotate to the cut-off wind speed Vout when it stops rotating. Up to the wind speed Vd, as the wind speed V increases, the power generation value also increases, but when the wind speed is above the wind speed Vd, the The generated power becomes fixed. In the operation control device 12, from the cut-in wind speed Vin to the wind speed Va, the generator torque is controlled in such a way that the rotational speed is fixed (to become Wlow), and the generated power is generated when the rotational speed is within the range of the wind speed Va to the wind speed Vb when the rotational speed is below the rated rotational speed Wrat. The generator torque is calculated and controlled according to the rotation speed in the way that the wind speed reaches the maximum. If the wind speed Vb is exceeded and the rotational speed reaches the rated rotational speed Wrat, the generator torque and the pitch angle are controlled in such a manner that the rated rotational speed Wrat is maintained. Basically, the generator torque is controlled in order to secure the generated power. Under the control of generator torque, within the range of wind speed Vb to wind speed Vd, the generator torque is changed according to the wind speed to reach the rated generator torque Qrat, and within the range of wind speed Vd to cut-off wind speed Vout, the rated value is maintained. The generator torque Qrat, and the generated power during this period is the rated generated power Prat. Under the control of the pitch angle, keep the pitch angle on the reverse side Θmin until the wind speed Vc, and change the pitch angle from the reverse side Θmin to the feathering according to the wind speed within the range from the wind speed Vc to the cut-off wind speed Vout side Θmax. However, in the example of FIG. 2, the control of the generator torque and the pitch angle are overlapped within the range of the wind speed Vc to the wind speed Vd, but it is also possible to set Vc=Vd to eliminate the overlap, and to control the generator torque And the control of the pitch angle is performed independently. In the low-load operation mode, for example, the speed and power generation are limited to a value less than the rated speed Wrat or the rated power Prat, or the limit value of the pitch angle on the reverse side is set to a value greater than Θmin. Compared with the operation in the operation mode, the wind power dissipation applied to the wind turbine generator 1 is relatively reduced to reduce the load.

FIG. 3 shows an example of the relationship between the transition occurrence interval and the occurrence frequency at a location where transition to the low-load operation mode occurs frequently. The horizontal axis of FIG. 3 represents the occurrence interval of the transition to the low-load operation mode, and the vertical axis represents the occurrence frequency. Although there are different situations depending on the installation location of the wind power generator 1 and seasonal changes, especially in places where the low-load operation mode transition occurs frequently, as shown in FIG. 3, the smaller the occurrence interval, the greater the occurrence frequency. , the possibility of continuous transition to the low-load operation mode in a short period of time is high. By lowering the transition threshold value only during the period in which such low-load operation mode transition occurs continuously, it is possible to reliably reduce the load and secure the power generation amount.

FIG. 4 is a block diagram showing an outline of an example of the operation control device 12 of the wind turbine generator 1 according to the first embodiment of the present invention. The operation control device 12 of the first embodiment includes a wind condition detection unit 101 , an operation mode determination unit 102 , a threshold value calculation unit 103 , a normal operation mode control unit 104 , a low load operation mode control unit 105 , and an operation mode selection unit 106 .

In the wind condition detection part 101, according to the input wind speed, wind direction and yaw angle, the wind condition data for switching the operation mode is detected and output. Furthermore, the wind direction is the angle formed between the direction the wind blows and the specific reference direction, and the yaw angle is the angle formed by the direction of the rotor (rotation axis) and the specific reference direction. The so-called "specific reference direction" is, for example, the reference direction with north being 0°. Furthermore, it is not limited to north, and the reference direction may be arbitrarily set. The yaw error is the difference between the wind direction and the yaw angle. In the operation mode determination unit 102, the wind condition data input from the wind condition detection unit 101 is compared with the threshold value input from the threshold value calculation unit 103, and when the wind condition data exceeds the threshold value, the output of selecting the low-load operation mode is output. The operation mode selection signal, in other cases, outputs the operation mode selection signal for selecting the normal operation mode. The threshold value calculation unit 103 normally outputs a preset threshold value, and outputs the set threshold value only during a specific period Tr after the operation mode selection signal input from the operation mode determination unit 102 changes from the normal operation mode to the low-load operation mode. The value at which the threshold is lowered is taken as the threshold.

The normal operation mode control unit 104 calculates the pitch angle command value of the blade 3 and the torque command value of the generator 6 in the normal operation mode without special restrictions according to the input rotor speed and the generated power, and uses them as the operation. Command value output. The low-load operation mode control unit 105 calculates the pitch angle command value of the blade 3 and the torque command of the generator 6 in the low-load operation mode in which the rotational speed and the generated power are limited based on the input rotor speed and power generation. value and output it as the operation command value. In the operation mode selection unit 106, the operation command value from the normal operation mode control unit 104 and the operation command value from the low load operation mode control unit 105 are switched by the operation mode selection signal from the operation mode determination unit 102, And output it as the final running command value.

FIG. 5 shows an example of the operation mode switching operation in the operation control device 12 of the first embodiment. The horizontal axis of FIG. 5 represents the time, and the vertical axis represents the yaw error, the threshold value of the yaw error, and the rotational speed limit value from the top of the figure. In this embodiment, the wind condition data for switching the operation mode is set as the value of the yaw error, and the rotational speed is reduced in the low-load operation mode. In addition, the threshold value for transition from the low load operation mode to the normal operation mode is the same as the threshold value for transition from the normal operation mode to the low load operation mode. Furthermore, "yaw error" is not strictly (narrowly) said to be the wind condition, but it is also the wind direction with the direction of the rotor (rotation axis) as the reference direction. ” also counts as a wind condition.

From time T1 when the yaw error indicated by the broken line exceeds the threshold value to time T5 after the predetermined period Tr has elapsed, the transition threshold value becomes the lower threshold value. As shown by the thick solid line, at time T2 and T4, the yaw error reaches below the reduced threshold value, and at time T3, the yaw error exceeds the reduced threshold value. The rotational speed limit value changes from the rated rotational speed Wrat to the reduced rotational speed Wlim (low-load operation mode) at times T1 and T3, and returns to the rated rotational speed Wrat (normal operation mode) at times T2 and T4. However, the transition from the rated rotational speed Wrat to the reduced rotational speed Wlim takes a certain amount of time. Therefore, shortly after time T1, the rotational speed does not change as much as the increase in the yaw error, and at time T3, which occurs at the reduced threshold, the rotational speed has been reduced before the yaw error increases. When the threshold value is not lowered, the transition to decreasing the rotational speed Wlim starts after reaching the time T3 ′, so the change in the rotational speed is less than the increase in the yaw error as in the case immediately after the time T1 . In FIG. 5 , in order to simplify the description, the case where the yaw error in the specific period Tr exceeds the normal threshold is set as one time, but when the increase in the yaw error in the specific period Tr occurs multiple times, the load reduction effect is great. Furthermore, the specific period Tr is determined by measuring the wind condition in advance at the installation site of the wind power generator, and taking into consideration the occurrence interval at which the occurrence frequency shown in FIG. 3 becomes sufficiently small. In addition, for the specific period Tr, the wind power condition after the wind power generation device is started to be used may be stored in advance, and the specific period Tr may be re-determined in consideration of the stored wind power condition.

In this way, once the transition to the low-load operation mode occurs, the threshold for transitioning from the normal operation mode to the low-load operation mode is lowered for a certain period, thereby switching from the normal operation mode when wind conditions such as increased load persist. The early transition to the low-load operation mode (time T3 in FIG. 5 ) can reliably reduce the load. In addition, when the load is not increased due to a change in the wind condition, the power generation amount can be ensured by returning to the normal threshold value. Furthermore, according to the present embodiment, the threshold value for transitioning from the normal operation mode to the low-load operation mode under wind conditions where the possibility of operation in the low-load operation mode is not high can be set high. In this case, it is possible to further prevent the reduction of the power generation amount.

In addition, it is difficult to fully lock the period when the low-load operation mode is likely to occur according to the wind direction and wind speed, and it is also considered that the response is slow when statistical values such as wind direction and wind speed are used. In this embodiment, once the low-load operation mode occurs When the load operation mode is changed, the threshold value for changing from the normal operation mode to the low load operation mode is lowered within a certain period, so that the operation of the wind power generator can be easily realized in consideration of the period during which the low load operation mode is likely to occur. [Example 2]

Using FIG. 6 , the wind power generator in the second embodiment will be described. In addition, the detailed description of the point which overlaps with Example 1 is abbreviate|omitted. In this embodiment, the threshold value calculation unit 103 usually outputs a threshold value set in advance (threshold value for transition from the normal operation mode to the low-load operation mode), and the operation mode selection signal input from the operation mode determination unit 102 is low. During the period of the load operation mode and the specific period Tr after changing from the low load operation mode to the normal operation mode, a value obtained by lowering the set threshold value is output as the threshold value for the transition from the normal operation mode to the low load operation mode. In addition, when the transition from the low-load operation mode to the normal operation mode occurs again in the specific period Tr, the threshold value calculating unit 103 outputs the lowered transition threshold value during another specific period Tr from that point in time.

FIG. 6 shows an example of the operation mode switching operation in the operation control device 12 of the second embodiment. The horizontal axis of FIG. 6 represents the time, and the vertical axis from the top of the figure represents the standard deviation of the wind speed, the threshold value of the standard deviation of the wind speed, and the power generation limit value. In this embodiment, the wind condition data for switching the operation mode is set as the standard deviation of the wind speed, and the generated power is reduced in the low-load operation mode. Also, the threshold value for transition from the low-load operation mode to the normal operation mode (normal operation mode transition threshold value) is set to a value smaller than the threshold value for transition from the normal operation mode to the low-load operation mode (low-load operation mode transition threshold value) ( FIG. 6 . single-point chain line in the middle) to prevent frequent pattern changes.

From the time T1 when the standard deviation of the wind speed shown by the dotted line exceeds the threshold value in normal time, the threshold value of the transition to the low-load operation mode shown by the thick solid line decreases, and the standard deviation of the wind speed becomes the normal operation mode shown by the single-dot chain line. The decreasing state continues from time T2 below the threshold to time T5 after the predetermined period Tr. Furthermore, during the low-load operation mode transition threshold reduction period, the transition to the low-load operation mode is performed at time T3, and the transition to the normal operation mode is performed again at time T4. Therefore, the reduction period of the low-load operation mode transition threshold value is extended from time T4 by a predetermined period Tr, This is maintained until time T6. After time T6, the low-load operation mode transition threshold is restored to the normal threshold before time T1.

The limit value of the generated power is changed from the rated generated power Prat to the reduced generated power Plim at times T1 and T3, and is restored to the rated generated power Prat at times T2 and T4. As in the case of the rotation speed of the first embodiment, since it takes a certain time to change from the rated power generation power Prat to the reduced power generation power Plim, in this embodiment, by lowering the threshold value of the transition to the low-load operation mode, it is also possible at time T3 By shifting to the low-load operation mode early, it is possible to reduce the load during the duration of wind conditions such as an increase in the load. In addition, by extending the reduction period of the low-load operation mode transition threshold value, the threshold value of the wind-force condition duration period similar to an increase in the load can be continuously reduced, so that the effect of reducing the load can be improved. Further, by setting the threshold value for transition from the low load operation mode to the normal operation mode to a value smaller than the threshold value for transition from the normal operation mode to the low load operation mode, frequent operation mode changes can be prevented.

In addition, the specific period Tr is the same as that of Example 1. The wind condition is measured in advance at the installation site of the wind power generator, and the determination is made in consideration of the occurrence interval at which the occurrence frequency shown in FIG. 3 becomes sufficiently small. In addition, for the specific period Tr, the wind power condition after the wind power generation device is started to be used may be stored in advance, and the specific period Tr may be re-determined in consideration of the stored wind power condition. In addition, since the specific period Tr in this embodiment counts the time from the point of returning to the normal operation mode as a starting point, it is possible to easily lengthen the lowering period of the low-load operation mode transition threshold value. In addition, it is not necessary to set the specific period Tr longer than a necessary time length, and the low-load operation mode transition threshold value corresponding to the actual wind condition can be lowered. [Example 3]

Using FIG. 7, the wind power generation apparatus in Example 3 is demonstrated. In addition, the detailed description is abbreviate|omitted about the point which overlaps with Example 1 and Example 2. In the present embodiment, as in the second embodiment, the threshold value calculation unit 103 usually outputs a preset threshold value (threshold value for transition from the normal operation mode to the low-load operation mode), and the input from the operation mode determination unit 102 outputs the threshold value. During the period when the operation mode selection signal is in the low-load operation mode, and between the specified period Tr after changing from the low-load operation mode to the normal operation mode, the value obtained by lowering the set threshold value is output as the transition from the normal operation mode to the low-load operation mode. threshold for transformation. Furthermore, if the transition from the low-load operation mode to the normal operation mode occurs again in the specific period Tr, the threshold value calculation unit 103 outputs the reduced transition threshold value between that time point and the specific period Tr. However, this embodiment differs from Embodiment 2 in that the low-load operation mode transition threshold changes in a ramp-like manner between the specific periods Tr, and finally becomes a normal low-load operation mode transition threshold.

FIG. 7 shows an example of the operation mode switching operation in the operation control device 12 of the third embodiment. The horizontal axis of FIG. 7 represents time, and the vertical axis from the top of the figure represents the standard deviation of the wind direction, the threshold value of the standard deviation of the wind direction, and the limit value on the reverse side of the pitch angle. In the present embodiment, the wind condition data for switching the operation mode is set as the standard deviation of the wind direction, and the limit value of the pitch angle on the reverse side is changed in the low-load operation mode. In addition, the threshold value for transition from the low load operation mode to the normal operation mode is the same as the threshold value for transition from the normal operation mode to the low load operation mode.

From time T1 when the standard deviation of the wind direction shown by the dotted line exceeds the threshold value in normal time, the threshold value shown by the thick solid line decreases, from time T2 when the standard deviation of the wind direction becomes below the transition threshold value to time T5 after the specified period Tr, Ramp-like change and continue to decrease. In addition, in FIG. 7 , as described below, the low-load operation mode is shifted again during the specific period Tr. Therefore, although the solid line of the transition threshold value until time T5 is not shown, during the specific period Tr, the When there is no transition to the low-load operation mode, the threshold changes in a ramp-like manner to the time T5 and returns to the normal threshold. Then, during the transition threshold value reduction period, at time T3 when the standard deviation of the wind direction exceeds the transition threshold value that changes in a ramp-like manner, the transition to the low-load operation mode is performed, and the transition threshold value becomes the same threshold value as the transition threshold value after the reduction at the time point T1. (The ramp-like change of the transition threshold is reset). Furthermore, at the time T4 when the standard deviation of the wind direction becomes less than or equal to the transition threshold value, the transition to the normal operation mode is performed again. Therefore, the lowering period of the low-load operation mode transition threshold value is counted from the time T4 for a specific period Tr, and changes in a ramp shape until the time T6. Return to normal thresholds (the end of the lowering period extends from T5 to T6).

The pitch angle limit value on the reverse side is changed from Θmin to Θlim on the feather side at times T1 and T3 to dissipate the wind, and returns to Θmin at times T2 and T4. As in the case of the rotation speed of Example 1, since it takes a certain time to change from Θmin to Θlim, by lowering the threshold for transitioning to the low-load operation mode, the transition to the low-load operation mode can be made earlier at time T3, and the similar load can be reduced. The load during the duration of the increased wind condition. In addition, by gradually returning the lowered threshold value to the normal threshold value in the predetermined period Tr, when the situation such as the change of wind force and the increase of the load disappears, the transition of the threshold value becomes smooth and the power generation amount can be secured.

Furthermore, in the above-mentioned embodiment, the threshold value is changed in a ramp shape, but it can also be changed in a curve shape or a step shape. In addition, in the above-mentioned embodiment, the threshold is changed in a ramp-like manner and is changed to be consistent with the normal threshold after the specific period Tr, but it may not be necessary to make it consistent with the normal threshold after the specific period Tr, and the specific The time point after the period Tr makes it stepwise into a normal threshold.

In addition, regarding the wind force condition data and the low-load operation mode, those described in the above-mentioned embodiments are only examples, and are not limited to them. For example, as the wind condition data, in addition to the instantaneous value of the yaw error similar to Embodiment 1, the instantaneous value of the wind speed and the wind direction can also be used, except that the standard deviation of the standard deviation of the wind speed and the standard deviation of the wind direction are similar to those of the Embodiments 2 and 3. In addition, statistical values such as wind speed, wind direction, and average yaw error can also be used. Moreover, in the low-load operation mode, in addition to the control of the generated power, the rotational speed, and the pitch angle (reverse pitch side), the torque may be controlled as an index.

Furthermore, in the above-mentioned embodiment, the following wind-type wind-power generator is described as an example of the wind-power generator, but it can also be applied to an upwind-type wind generator. Moreover, it is not limited to the wind power generation apparatus installed on the ground, and it is applicable also to the offshore wind power generation apparatus of a floating body type or an implantation type.

In addition, the present invention is not limited to the above-described embodiments, and includes various modifications. For example, the above-mentioned embodiments have been described in detail in order to explain the present invention in a simple and intelligible manner, but are not necessarily limited to those having all the components described. In addition, a part of the configuration of a certain embodiment can be replaced with the configuration of another embodiment, and the configuration of another embodiment can also be added to the configuration of a certain embodiment. In addition, it is possible to add, delete, and replace other configurations with respect to some of the configurations of the respective embodiments.

1: Wind power plant 2: Wheel hub 3: Blades 4: Rotor 5: Cabin 6: Generator 7: Wind direction anemometer 8: Speed sensor 9: Pitch angle adjustment device 10: Tower 11: Yaw angle adjustment device 12: Operation control device 101: Wind condition detection section 102: Operation mode decision section 103: Threshold calculation section 104: Normal operation mode control unit 105: Low-load operation mode control unit 106: Operation mode selection part Plim: reduce power generation Prat: rated power generation Qrat: rated generator torque T1: Moment T2: Moment T3: Moment T3': Moment T4: Moment T5: Moment T6: Moment Tr: specific period Va: wind speed Vb: wind speed Vc: wind speed Vd: wind speed Vin: cut in wind speed Vout: cut off the wind speed Wlim: Reduce RPM Wlow: RPM Wrat: rated speed

FIG. 1 is a diagram showing an outline of the configuration of a wind turbine generator according to an embodiment of the present invention. FIG. 2 is a schematic diagram showing an example of the relationship between the generated power, the generator rotational speed, the generator torque, and the pitch angle of the wind turbine generator. 3 is a schematic diagram showing an example of the relationship between the transition occurrence interval and the occurrence frequency at a point where transitions to the low-load operation mode frequently occur. FIG. 4 is a block diagram showing an outline of an operation control unit of the wind turbine generator according to the first embodiment. FIG. 5 is a schematic diagram showing an example of the operation mode switching operation in the first embodiment. FIG. 6 is a schematic diagram showing an example of the operation mode switching operation in the second embodiment. 7 is a schematic diagram showing an example of the operation mode switching operation in the third embodiment.

T1: Moment

T2: Moment

T3: Moment

T3': Moment

T4: Moment

T5: Moment

Tr: specific period

Wlim: Reduce RPM

Wrat: rated speed

Claims (9)

A wind power generator is characterized in that: it has a normal operation mode and a low load operation mode, the low load operation mode makes the load acting on the wind power generator lower than that in the normal operation mode; and the wind power generator has an operation control device, the above-mentioned operation control device transitions from the above-mentioned normal operation mode to the above-mentioned low-load operation mode when the wind condition data exceeds the threshold value of transition from the above-mentioned normal operation mode to the above-mentioned low-load operation mode, that is, the low-load operation mode transition threshold; and once When the wind condition data exceeds the low-load operation mode transition threshold value and the normal operation mode is switched to the low-load operation mode, the operation control device reduces the low-load operation mode transition threshold value and maintains the reduced state for a specific period of time. . The wind power generator of claim 1, wherein the operation control device has a normal operation mode transition threshold, the normal operation mode transition threshold being a threshold for transition from the low-load operation mode to the normal operation mode for the wind condition data, the The operation control device changes from the low-load operation mode to the normal operation mode when the wind condition data becomes less than the normal operation mode transition threshold value; the specific period is to restore from the low-load operation mode to the normal operation mode again. time point begins. The wind power generator according to claim 2, wherein the operation control device transitions from the normal operation mode between the specific periods In the case of the above-mentioned low-load operation mode, the above-mentioned specific period starts again from the time point when the above-mentioned low-load operation mode returns to the above-mentioned normal operation mode. The wind power generator according to claim 2, wherein the operation control device reduces the degree of reduction of the low-load operation mode transition threshold value between the specific periods. The wind power generator of claim 1, wherein the operation control device has a normal operation mode transition threshold, and the normal operation mode transition threshold is a threshold for transitioning from the low-load operation mode to the normal operation mode for the wind condition data, and converts the The normal operation mode transition threshold is set to a value smaller than the low load operation mode transition threshold, and when the wind condition data becomes below the normal operation mode transition threshold, the low load operation mode is switched to the normal operation mode. The wind power generator of claim 1, wherein the operation control device has a normal operation mode transition threshold, and the normal operation mode transition threshold is a threshold for transitioning from the low-load operation mode to the normal operation mode for the wind condition data, and converts the The low-load operation mode transition threshold value and the normal operation mode transition threshold value are set to the same value, and when the wind condition data becomes below the normal operation mode transition threshold value, the upper The low-load operation mode is shifted to the normal operation mode described above. The wind power generation device of claim 1, wherein the wind condition data includes at least one of the instantaneous value or statistical value of wind speed, wind direction, or yaw error. The wind power generator according to claim 1, wherein the operation control device controls in the following manner: in the low-load operation mode, the hub rotational speed of the wind power generator or the generator output of the wind power generator is made smaller than the normal operation mode The hub speed of the above wind power generation device or the generator output of the above wind power generation device. The wind power generator according to claim 1, wherein the operation control device performs control in the following manner: in the low-load operation mode, the limit value on the reverse side of the pitch angle of the blades of the wind power generator is set to be higher than the normal limit value. In the operation mode, the limit value of the pitch angle of the blades of the wind power generator on the reverse side is closer to the feather side.

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